Oncologic efficacy of gonadotropin-releasing hormone agonist in hormone receptor-positive very young breast cancer patients treated with neoadjuvant chemotherapy

Table 1 Patient characteristics according to age group

Variable	≤ 35 yr group (n = 78), n (%)	> 35 yr group (n = 353), n (%)	P value
BMI			0.064
≤ 25	56 (71.8)	211 (59.7)
> 25	22 (28.2)	142 (40.23
Clinical tumor stage			0.187
cT1	8 (10.26)	15 (4.25)
cT2	36 (46.15)	184 (52.12)
cT3	26 (33.33)	120 (33.99)
cT4	8 (10.26)	34 (9.63)
Clinical node stage			0.237
cN1	14 (17.95)	96 (27.20)
cN2	40 (51.28)	162 (45.89)
cN3	24 (30.77)	95 (26.91)
Pathologic tumor stage			0.101
ypT0-is	15 (19.23)	34 (9.63)
ypT1	23 (29.49)	116 (32.86)
ypT2	25 (32.05)	111 (31.44)
ypT3	15 (19.23)	84 (23.80)
ypT4	0 (0.00)	8 (2.27)
Pathologic node stage			0.336
ypN0	25 (32.05)	110 (31.16)
ypN1	30 (38.46)	111 (31.44)
ypN2	18 (23.08)	86 (24.36)
ypN3	5 (6.41)	46 (13.03)
Lymphovascular invasion			0.739
Present	38 (48.72)	168 (47.59)
Absent	32 (41.03)	157 (44.48)
Unknown	8 (10.26)	28 (7.93)
Surgery			0.195
Breast conserving	43 (55.13)	166 (47.03)
Mastectomy	35 (44.87)	187 (52.97)
Nuclear grade			0.697
Low	11 (14.10)	37 (10.48)
Intermediate	32 (41.03)	165 (46.74)
High	27 (34.62)	121 (34.28)
Unknown	8 (10.26)	30 (8.50)
Radiation therapy			0.642
Yes	75 (96.15)	335 (94.90)
No	3 (3.85)	18 (5.10)
GnRH agonist			< 0.001
Yes	22 (52.4)	20 (11.2)
No	20 (47.6)	158 (88.8)

GnRH: Gonadotropin-releasing hormone; BMI: Body mass index.